Technical Field
The present disclosure is directed to a microfluidic delivery system including a die having multiple heaters in a single chamber.
Description of the Related Art
Microfluidic die are utilized in printers for ejection of drops of ink onto paper. FIG. 1 is an enhanced view of a fluidic path from an inlet 7 into a chamber 17 and through a nozzle 11 of a microfluidic die 13 of a known type. The nozzle 11 is formed through a nozzle plate 15 that is positioned over the chamber 17. In this view, the nozzle plate 15 has been cut along a center line of the nozzle to show a cross-section of the nozzle 11. In particular, the nozzle 11 has a lower opening 19 with a first diameter 29 that is significantly larger than a second diameter 31 of an upper opening 21. Walls of the nozzle are sloped between the lower opening 19 and the upper opening 21.
FIG. 2A is a top down view showing relative sizes of elements of the microfluidic die of FIG. 1. FIG. 2B is a cross-section view along line 2B-2B of FIG. 2A. The die 13 includes a single heater 23 that is positioned below the chamber 17. The heater 23 may be square with sides that each has a first dimension 25. The chamber 17 is also square, with sides each having a second dimension 27. The nozzle 11 includes the lower opening 19, which is larger than area of the chamber 17. The nozzle 11 includes the much smaller upper opening 21, which has the second diameter 31.
The heater 23 is configured to heat ink in the chamber 17. As the heater 23 reaches a threshold temperature, a bubble is formed in the chamber 17. When the bubble explodes, ink is ejected out of the nozzle. As the bubble explodes, ink that is not ejected can be pushed back into the inlet. This can create inefficiencies the microfluidic die.